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Date: Wed, 4 Mar 2015 14:32:54 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20150304063254.GD19563@ad.nay.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v5 04/13] quorum: Fix close path
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To: Max Reitz <mreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-block@nongnu.org, qemu-devel@nongnu.org, Markus Armbruster <armbru@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>

On Tue, 03/03 15:13, Max Reitz wrote:
> bdrv_unref() can lead to bdrv_close(), which in turn will result in
> bdrv_drain_all(). This function will later be called blk_drain_all() and
> iterate only over the BlockBackends for which blk_is_inserted() holds
> true; therefore, bdrv_is_inserted() and thus quorum_is_inserted() will
> probably be called.
> 
> This patch makes quorum_is_inserted() aware of the fact that some
> children may have been closed already.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  block/quorum.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/quorum.c b/block/quorum.c
> index 7a75cea..5ae2398 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -1005,6 +1005,7 @@ static void quorum_close(BlockDriverState *bs)
>  
>      for (i = 0; i < s->num_children; i++) {
>          bdrv_unref(s->bs[i]);
> +        s->bs[i] = NULL;
>      }
>  
>      g_free(s->bs);
> @@ -1070,7 +1071,7 @@ static bool quorum_is_inserted(BlockDriverState *bs)
>      int i;
>  
>      for (i = 0; i < s->num_children; i++) {
> -        if (!bdrv_is_inserted(s->bs[i])) {
> +        if (s->bs[i] && !bdrv_is_inserted(s->bs[i])) {
>              return false;
>          }
>      }
> -- 
> 2.1.0
> 

Reviewed-by: Fam Zheng <famz@redhat.com>